Potential Anti-Inflammatory and Chondroprotective Effect of Luzula sylvatica.

(1) Interest in the Juncaceae family has risen as some members have shown anti-inflammatory properties and interesting compounds. In this regard, we decided to investigate the antioxidant and anti-inflammatory properties of Luzula sylvatica, a Juncaceae not yet extensively studied, in the context of osteoarthritis. (2) The Luzula sylvatica Ethanol extract (LS-E) was used to test the production of reactive oxygen species (ROS) by leucocytes, the IL1ß and PGE2 production by peripheral blood mononuclear cells (PBMCs), the production of EP4, and the activation of NFκB in THP-1, as well as the IL1ß-activated normal human knee articular chondrocytes (NHAC-Kn) gene expression, grown in monolayers or maintained in alginate beads. (3) Organic acids, caffeoylquinic acids, quercetin and luteolin, compounds frequently found in this family were identified. The LS-E exhibited inhibited ROS formation. The LS-E did not affect NFκB activation and IL1ß secretion but dampened the secretion of PGE2 by PBMCs and the presence of EP4 in THP-1. It also modulated the expression of NHAC-Kn in both models and inhibited the expression of several proteases and inflammatory mediators. (4) Luzula sylvatica might supply interesting antioxidant protection against cartilage damages and lessen joint inflammation, notably by decreasing PGE2 secretion in the synovial fluid. Moreover, it could act directly on chondrocytes by decreasing the expression of proteases and, thus, preventing the degradation of the extracellular matrix.

Xanthine Oxidase Inhibitors from Filipendula ulmaria (L.) Maxim. and Their Efficient Detections by HPTLC and HPLC Analyses.

Filipendula ulmaria is a plant commonly used for the treatment of several pathologies, such as diarrhoea, ulcers, pain, stomach aches, fevers, and gout. Our study focused on the use of F. ulmaria for the treatment of gout disease. We first studied the chemical composition of a methanolic extract of the aerial parts and demonstrated its xanthine oxidase (XO) inhibitory activity. Then, we performed a fractionation and evaluated the most XO inhibitory active fractions by UV measurement. Purification of some fractions allowed the determination of the inhibitory activity of pure compounds. We demonstrated that spiraeoside, a glycosylated flavonoid, possesses an activity around 25 times higher than allopurinol, used as a reference in the treatment of gout disease. In order to easily and quickly identify potent inhibitors in complex matrix, we developed a complementary strategy based on an HPLC method and an Effect Directed Assay (EDA) method combining HPTLC and biochemical assays. The HPLC method, capable of determining compounds exhibiting interactions with the enzyme, could be an efficient strategy for evaluating potent enzyme inhibitors in a complex mixture. This strategy could be applied for quantitative assays using LC/MS experiments.

Anti-Inflammatory and Cytotoxic Potential of New Phenanthrenoids from Luzula Sylvatica.

Phenanthrenoids have been widely described, in the Juncaceae family, for theirbiological properties such as antitumor, anxiolytic, anti-microbial, spasmolytic, and antiinflammatoryactivities. The Juncaceae family is known to contain a large variety ofphenanthrenoids possessing especially anti-inflammatory and cytotoxic properties. Luzulasylvatica, a Juncaceae species, is widely present in the Auvergne region of France, but has neverbeen studied neither for its phytochemical profile nor for its biological properties. We investigatedthe phytochemical profile and evaluated the potential anti-inflammatory activities of L. sylvaticaaerial parts extracts. A bioassay-guided fractionation was carried out to identify the most activefractions. Nine compounds were isolated, one coumarin 1 and eight phenanthrene derivatives (2-9), including four new compounds (4, 5, 8 and 9), from n-hexane and CH2Cl2, fractions. Theirstructures were established by HRESIMS, 1D and 2D NMR experiments. The biological properties,especially the anti-inflammatory/antioxidant activities (ROS production) and antiproliferativeactivity on THP-1, a monocytic leukemia cell line, of each compound, were evaluated. Threephenanthrene derivatives 4, 6, and 7 showed very promising antiproliferative activities.Phenanthrene derivatives.

A Novel HPLC Method for Direct Detection of Nitric Oxide Scavengers from Complex Plant Matrices and Its Application to Aloysia triphylla Leaves.

The present study aimed at developing an original pre-column HPLC assay allowing rapid characterization of nitric oxide (NO) scavengers from complex plant extracts. Sodium nitroprusside (SNP) was employed as a NO donor and spiked with an aqueous extract from Aloysia triphylla leaves prior to HPLC analysis. Relying on the ability of radical scavenging constituents to be oxidized upon reaction with radicals, this assay successfully allowed direct identification of three potential NO scavengers, including verbascoside, isoverbascoside, and luteolin-7-O-diglucuronide. These three phenolics were also individually assessed for their NO scavenging activities by using a Griess colorimetric assay. With respective IC50 values of 56 ± 4, 51 ± 3, and 69 ± 5 µg/mL, verbascoside, isoverbascoside, and luteolin-7-O-diglucuronide were all reported as potent NO scavenging compounds, confirming the efficiency of the SNP spiking HPLC assay. The present method can, thus, be considered as a valuable and effective approach for speeding up the discovery of NO scavenging constituents.

A colorimetric assay adapted to fragment screening revealing aurones and chalcones as new arginase inhibitors.

Arginase, a difficult-to-target metalloenzyme, is implicated in a wide range of diseases, including cancer, infectious, and cardiovascular diseases. Despite the medical need, existing inhibitors have limited structural diversity, consisting predominantly of amino acids and their derivatives. The search for innovative arginase inhibitors has now extended to screening approaches. Due to the small and narrow active site of arginase, screening must meet the criteria of fragment-based screening. However, the limited binding capacity of fragments requires working at high concentrations, which increases the risk of interference and false positives. In this study, we investigated three colorimetric assays and selected one based on interference for screening under these challenging conditions. The subsequent adaptation and application to the screening a library of metal chelator fragments resulted in the identification of four compounds with moderate activity. The synthesis and evaluation of a series of compounds from one of the hits led to compound 21a with an IC50 value of 91.1 µM close to the reference compound piceatannol. Finally, molecular modelling supports the potential binding of aurones and chalcones to the active site of arginase, suggesting them as new candidates for the development of novel arginase inhibitors.

Arginase inhibitory activities of chemical constituents from Macaranga hurifolia Beille leaves.

The methanolic extract of the leaves of Macaranga hurifolia Beille showed arginase inhibitory activity (40% at 100 µg/mL) and was then fractionated to obtain nine polyphenolic compounds. Their structures were elucidated on the basis of NMR spectroscopic data, and by comparison with data previously reported in the literature, as gallic acid (1), 3,4-dihydroxybenzoic acid (2), chlorogenic acid, (3), corilagin (4), cynaroside (5), cosmosiin (6), hyperoside (7) isoquercitrin (8) and guajaverin (9). These compounds have been evaluated as arginase inhibitors. Compounds 4, 7, 8 and 9 showed varying arginase inhibitory activities with IC50 values ranging from 102 to 302 µM. All the isolated compounds were previously identified in this species but their activities on arginase are reported here for the first time.

Aspalathus linearis (Rooibos) Targets Adipocytes and Obesity-Associated Inflammation.

Excess weight and obesity are the fifth leading cause of death globally, and sustained efforts from health professionals and researchers are required to mitigate this pandemic-scale problem. Polyphenols and flavonoids found in Aspalathus linearis-a plant widely consumed as Rooibos tea-are increasingly being investigated for their positive effects on various health issues including inflammation. The aim of our study was to examine the effect of Rooibos extract on obesity and the associated low-grade chronic inflammatory state by testing antioxidant activity, cytokine secretions, macrophage polarization and the differentiation of human adipocytes through the development of adipospheroids. Rooibos extract significantly decreased ROS production and the secretion of pro-inflammatory cytokines (IFN-γ, IL-12, IL-2 and IL-17a) in human leukocytes. Additionally, Rooibos extract down-regulated LPS-induced macrophage M1 polarization, shown by a significant decrease in the expression of pro-inflammatory cytokines: TNFα, IL-8, IL-6, IL-1ß and CXCL10. In addition, Rooibos inhibited intracellular lipid accumulation and reduced adipogenesis by decreasing the expression of PPARγ, Ap2 and HSL in adipospheroids. A significant decrease in leptin expression was noted and this, more interestingly, was accompanied by a significant increase in adiponectin expression. Using a co-culture system between macrophages and adipocytes, Rooibos extract significantly decreased the expression of all studied pro-inflammatory cytokines and particularly leptin, and increased adiponectin expression. Thus, adding Rooibos tea to the daily diet is likely to prevent the development of obesity associated with chronic low-level inflammation.

Anti-obesity effects of the n-butanol fraction of the methanolic leaf extract of Artemisia campestris from Tunisian pharmacopeia in male Wistar rats.

OBJECTIVES: This study aimed to investigate the effect of the n-butanol fraction of the methanol leaf extract of Artemisia campestris (BFAC), growing wild in the arid zone of Tunisia, on induced obesity in male Wistar rats. METHODS: The total phenolic content and antioxidant capacity of the BFAC were estimated. The main phenolic composition of the BFAC was determined using the high-performance chromatography system coupled with a diode array detector technics. Five groups of rats received either a standard diet (SD group), a high-fat diet (HFD group), or an HFD supplemented with oral administration of BFAC for eight weeks. RESULTS: The BFAC showed higher phenolic content and antioxidant potential than the total leaf methanol extract. Chlorogenic acid, rutin, and dicaffeoylquinic acids were identified in the BFAC. HFD increased body and relative liver weights, as well as serum and hepatic levels of triglycerides and total cholesterol, compared to SD. HFD generated significant oxidative stress in the liver by increasing lipid peroxidation and reducing glutathione-S-transferase, catalase, and glutathione peroxidase activities, compared to SD. These HFD-altered parameters were restored to normal values by oral treatment with the BFAC. CONCLUSIONS: These findings give first evidence about the antiobesity efficacy of A. campestris. Such a study would enhance existing information and promote the use of this species.

Impact of Simulated Gastrointestinal Conditions on Antiglycoxidant and α-Glucosidase Inhibition Capacities of Cyanidin-3-O-Glucoside.

Cyanidin-3-O-glucoside (C3G) is a widespread anthocyanin derivative, which has been reported in vitro to exert potent antioxidant, antiglycation and α-glucosidase inhibition effects. Nevertheless, the physiological relevance of such properties remains uncertain considering its significant instability in gastrointestinal conditions. A simulated digestion procedure was thus instigated to assess the influence of gastric and intestinal media on its chemical integrity and biological activities. HPLC analyses of digested C3G samples confirmed the striking impact of intestinal conditions, as attested by a decomposition ratio of 70%. In contrast, with recovery rates of around 90%, antiglycation, as well as DPPH and ABTS scavenging assays, uniformly revealed a noteworthy persistence of its antiglycoxidant capacities. Remarkably, a prominent increase of its α-glucosidase inhibition activity was even observed after the intestinal phase, suggesting that classical in vitro evaluations might underestimate C3G antidiabetic potential. Consequently, the present data provide novel and specific insights on C3G's digestive fate, suggesting that the gastrointestinal tract does not profoundly affect its positive action on oxidative and carbonyl stresses. More specifically, it also tends to support its regulating effects on postprandial hyperglycemia and its potential usefulness for diabetes management.

Stability and Antiglycoxidant Potential of Bilberry Anthocyanins in Simulated Gastrointestinal Tract Model.

Anthocyanins from Vaccinium myrtillus fruits have been reported in vitro to exert potent radical scavenging and antiglycation activities. However, the physiological relevance of such properties remains unclear given the potential susceptibility of anthocyanin derivatives to digestive conditions. A simulated gastrointestinal tract model was thus implemented to assess the impact of gastric and intestinal phases on the chemical integrity of bilberry anthocyanins and their antiglycoxidant effects. Results demonstrated that the investigated activities as well as total and individual anthocyanin contents were marginally affected by gastric conditions. By contrast, with recoveries ranging from 16.1 to 41.2%, bilberry anthocyanins were shown to be highly sensitive to the intestinal phase. Of major interest, a much better preservation was observed for radical scavenging and antiglycation activities as attested by recovery rates ranging from 79.1 to 86.7%. Consistently with previous observations, the present study confirms the moderate bioaccessibility of anthocyanin constituents. It does however provide valuable information supporting the persistence of substantial radical scavenging and antiglycation activities at each step of the digestion process. Taken together, these data indicate that digestive conditions might not abolish the potential positive effects of bilberry consumption on both oxidative and carbonyl stresses.

Screening and Characterization of Antiglycoxidant Anthocyanins from Vaccinium myrtillus Fruit Using DPPH and Methylglyoxal Pre-Column HPLC Assays.

Vaccinium myrtillus fruit (bilberry) is well known for its high richness in anthocyanins, which may be responsible for its preventive effects on several oxidative and carbonyl stress-related pathologies. However, limited data are available regarding the antioxidant and antiglycative contributions of its constituents. Spectrometric analyses were performed to evaluate anthocyanin content, radical scavenging and antiglycative properties of an anthocyanin-rich extract from bilberries. Additionally, original DPPH and methylglyoxal pre-column HPLC methods were instigated to allow straightforward identification of the main contributors to radical and carbonyl trapping effects. Finally, representative pure anthocyanins were evaluated using classical DPPH and antiglycation assays. Delphinidin, petunidin and cyanidin glycosides were identified as the most effective radical scavenging constituents in both HPLC and spectrometric DPPH evaluations. Potent antiglycative activities were also assessed for cyanidin, delphinidin and petunidin glucosides as attested by their respective IC50 values of 114.2 ± 7.8, 130.5 ± 2.8, and 132.4 ± 3.7 µM. Interestingly, methylglyoxal spiking evaluation demonstrated that all bilberry anthocyanins exerted noticeable and comparable α-dicarbonyl trapping effects. Anthocyanins can be regarded as potent antiglycoxidant agents that might account for some health benefits of bilberries consumption. Besides, significant differences in their contributions were successfully highlighted by the employed pre-column HPLC assays.

1H NMR-based metabolomics of antimalarial plant species traditionally used by Vha-Venda people in Limpopo Province, South Africa and isolation of antiplasmodial compounds.

ETHNOPHARMACOLOGICAL RELEVANCE: The Vha-Venda people living in rural areas of Limpopo Province of South Africa regularly use traditional plant-based medicines to treat malaria. In our earlier publication, twenty indigenous plant species used to treat malaria or its symptoms by Vha-Venda people were evaluated for antiplasmodial activity. The main objective of the current study was to assess the robustness of NMR-based metabolomics in discriminating classes of secondary compounds that are responsible for the observed antimalarial activity and the isolation of antiplasmodial compounds. MATERIALS AND METHODS: Twenty dichloromethane extracts were reconstituted in CDCl3, subjected to 1H NMR-based metabolomic analysis on a Varian 600 MHz spectrometer and the acquired 1H NMR spectra were then evaluated collectively using multivariate data analysis (MDA). Principal Component Analysis (PCA) and Orthogonal Projections to Latent Structures-Discriminant Analysis (OPLS-DA) were used to 'globally' discern antiplasmodial profiles. A contribution plot was then generated from the OPLS-DA scoring plot in an attempt to determine the classes of compounds that are responsible for the observed grouping. Further phytochemical analyses were conducted on the lipophilic extracts of Tabernaemontana elegans and Vangueria infausta subsp. infausta. These best candidates were fractionated, purified and their isolated compounds identified based on conventional chromatographic and spectroscopic techniques. RESULTS: The PCA did not separate the acquired profiles according to the detected antiplasmodial bioactivity. Application of a supervised OPLS-DA on the 1H NMR profiles resulted in a discrimination pattern that could be correlated to the observed antimalarial bioactivity. A contribution plot generated from the OPLS-DA scoring plot illustrated the classes of compounds responsible for the observed grouping. Prominent peaks were observed in the aromatic, sugar-based/N-containing and aliphatic spectral regions of the contribution plot. Two known indole alkaloids were isolated from T. elegans, and identified as tabernaemontanine (IC50 = 12.0 ±â€¯0.8 µM) and dregamine (IC50 = 62.0 ±â€¯2.4 µM). Friedelin (IC50 = 7.20 ±â€¯0.5 µM) and morindolide (IC50 = 107.1 ±â€¯0.6 µM) were isolated from V. infausta subsp. infausta. This is the first report of the rare iridoid lactone, morindolide's antimalarial activity. While these two compounds have been previously identified, this is the first account of their occurrence in the genus Vangueria. CONCLUSION: The study illustrated the potential of NMR-based metabolomics in discriminating classes of compounds that may be attributed to antiplasmodial activity. Additionally, the study demonstrated the potential of discovering novel antiplasmodial scaffolds from medicinal plants and the rationale for the bioprospecting antimalarial plant species used by Vha-Venda people.

In Vitro Anti-Inflammatory and Immunomodulatory Activities of an Extract from the Roots of Bupleurum rotundifolium.

BACKGROUND: Some Bupleurum species, such as the Bupleurum chinense DC. or the Bupleurum scorzonerifolium Willd have been extensively studied (especially their roots) for the treatment of inflammation. In contrast, only compounds extracted from the aerial parts of Bupleurum rotundifolium have been studied and showed anti-inflammatory or antiproliferative activities. This study was conducted to investigate the antioxidant, anti-inflammatory, and immunomodulatory effects of Bupleurum rotundifolium roots. METHODS: To tackle the various aspects of inflammation, we studied in vitro a methanolic extract from the roots of Bupleurum rotundifolium on peripheral blood mononuclear cells (PBMCs), polymorphonuclear neutrophils (PMNs), and the monocytic cells THP-1. Its antioxidant capacities and iron-chelating activity were assessed. The extract was tested on THP-1 differentiation, reactive oxygen species (ROS) production by leukocytes, neutrophils chemotaxis, cytokines, PGE2 production, and NF-κB activation in PBMCs. RESULTS: The extract showed a decreased ROS production in stimulated cells. It increased PBMC chemokine secretion and up-regulated the differentiation of THP-1 monocytes into macrophage-like cells, indicating a potential interest of the extract in the resolution of acute inflammation. In addition, the analysis of cytokine production suggests that Bupleurum rotundifolium has immunomodulatory properties. CONCLUSIONS: Cytokines secretion, especially IL-1ß and IL-12p70, provided us with a set of indicators suggesting that the extract might be able to drive the polarization of macrophages and lymphocytes toward a Th2 anti-inflammatory profile in excessive inflammation.

The fruit of Annona squamosa L. as a source of environmental neurotoxins: From quantification of squamocin to annotation of Annonaceous acetogenins by LC-MS/MS analysis.

Annonaceous acetogenins (AAGs) are neurotoxins possibly responsible for atypical Parkinsonism/dementia clusters, via the consumption of edible Annonaceae fruits. Their presence was investigated in fruit pulps of Annona squamosa from different locations. Qualitative analysis of other AAGs was performed. We here report the identification of squamocin in batches from Asia, the Caribbean Basin and the Indian Ocean. This molecule was quantified by HPLC-UV, evidencing a content of 13.5-36.4mg/fruit. HPLC-ESI-Q-TOF allowed the detection of 25 different raw formulas matching with AAGs. LC-MS/MS methodological development was performed using 4 representative standards. The main AAGs could be annotated, including bullatacin (rolliniastatin-2) and annonacin. This study evidences a remarkable homogeneity for the main AAGs within the species, and discrepancies for minor compounds. These findings indicate that A. squamosa should be considered a risk factor for neurodegenerative disorders.

Identification of anti-HIV active dicaffeoylquinic- and tricaffeoylquinic acids in Helichrysum populifolium by NMR-based metabolomic guided fractionation.

South Africa being home to more than 35% of the world's Helichrysum species (c.a. 244) of which many are used in traditional medicine, is seen potentially as a significant resource in the search of new anti-HIV chemical entities. It was established that five of the 30 Helichrysum species selected for this study had significant anti-HIV activity ranging between 12 and 21 µg/mL (IC50) by using an in-house developed DeCIPhR method on a full virus model. Subsequent toxicity tests also revealed little or no toxicity for these active extracts. With the use of NMR-based metabolomics, the search for common chemical characteristics within the plant extract was conducted, which resulted in specific chemical shift areas identified that could be linked to the anti-HIV activity of the extracts. The NMR chemical shifts associated with the activity were identified to be 2.56-3.08 ppm, 5.24-6.28 ppm, 6.44-7.04 ppm and 7.24-8.04 ppm. This activity profile was then used to guide the fractionation process by narrowing down and focusing the fractionation and purification processes to speed up the putative identification of five compounds with anti-HIV activity in the most active species, Helichrysum populifolium. The anti-HIV compounds identified for the first time from H. populifolium were three dicaffeoylquinic acid derivatives, i.e. 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid as well as two tricaffeoylquinic acid derivatives i.e. 1,3,5-tricaffeoylquinic acid and either 5-malonyl-1,3,4-tricaffeoylquinic or 3-malonyl-1,4,5-tricaffeoylquinic acid, with the latter being identified for the first time in the genus.

New insights into the mechanisms of the vasorelaxant effects of apocynin in rat thoracic aorta.

Apocynin is a naturally occurring acetophenone widely used as an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Recent data suggested that apocynin might exert NADPH oxidase-independent pharmacological properties. Among them, vasorelaxant properties have been described, but the mechanisms still give rise to debates. The present study investigated the mechanisms involved in the vasorelaxant effect of apocynin on the in vitro model of rat isolated thoracic aortic rings. Apocynin (30 µM to 10 mM) induced a dose-dependent relaxation in both endothelium-intact and endothelium-denuded aortic rings with respective EC50 values of 0.78 ± 0.08 and 1.91 ± 0.21 mM. Endothelium removal or inhibition of nitric oxide (NO) synthase with N(ω)-nitro-L-arginine-methyl ester (L-NAME) significantly decreased but did not abolish the effect of apocynin. By contrast, apocynin-induced relaxation was unchanged after incubation with indomethacin or charybdotoxin plus apamin. In endothelium-denuded aortas, the vasorelaxant effect of apocynin was significantly reduced by glibenclamide but not by 4-aminopyridine nor by iberiotoxin. Apocynin significantly decreased Ca(2+)-induced contraction and inhibited intracellular Ca(2+) mobilization after contraction with phenylephrine. Finally, the acute intravenous injection of apocynin led to an immediate and transient hypotensive effect in spontaneously hypertensive rats (SHR). In conclusion, our data demonstrated that apocynin induces both endothelium-independent relaxant effects involving inhibition of Ca(2+) mobilization and activation of KATP channels in vascular smooth muscle cells and endothelium-dependent effects mediated by NO. These results should provide a basis for caution when interpreting results on the vascular effects of apocynin.

Vasorelaxant effects and mechanisms of action of Heracleum sphondylium L. (Apiaceae) in rat thoracic aorta.

ETHNOPHARMACOLOGICAL RELEVANCE: Aerial parts of Heracleum sphondylium L. (HS) are used in traditional medicine to treat hypertension. To provide pharmacological basis for this use, we investigated the vasorelaxant effects of a dichloromethane extract of HS (HSDE) and the mechanisms involved. MATERIALS AND METHODS: Activity of HSDE was evaluated on rat isolated thoracic aortic rings. RESULTS: HSDE induced vasorelaxation in phenylephrine (PE, 10(-6)mol/L) and high KCl-(6×10(-2)mol/L) pre-contracted aortic rings that was independent on the presence of endothelium. HSDE markedly decreased extracellular Ca(2+)-induced contraction in high-KCl and PE pre-challenged rings. It also inhibited the intracellular Ca(2+) release sensitive to PE (10(-6)M). The relaxant effect of HSDE were blunted by 4-amino-pyridine (4-AP, 10(-3)mol/L), an inhibitor of voltage-dependent K(+) channels. CONCLUSION: Our results provide the first evidence that a dichloromethane extract of Heracleum sphondylium L. exhibits vasorelaxant properties through endothelium-independent mechanisms involving the inhibition of Ca(2+) mobilization and changes in Kv channel conductances. These data argue for its use as antihypertensive therapy in traditional medicine.

Vasorelaxant and hypotensive effects of a hydroalcoholic extract from the fruits of Nitraria sibirica Pall. (Nitrariaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Fruits of Nitraria sibirica Pall. are traditionally used in Uighur medicine to treat hypertension. This study aimed to support that folk use by defining their vasoactive and hypotensive properties. MATERIALS AND METHODS: The vasorelaxant activity and the underlying mechanisms of a hydroalcoholic extract from the fruits of Nitraria sibirica Pall. (NSHE) were evaluated on thoracic aortic rings isolated from Wistar rats. In addition, the acute hypotensive effect of NSHE was assessed in anesthetized spontaneously hypertensive rats (SHR) and in their normotensive control Wistar Kyoto (WKY) rats. RESULTS: NSHE (0.1-10 g/l) was clearly more effective to induce vasodilation of phenylephrine- (PE, 1 µM) than high KCl- (60mM) pre-contracted aortic rings with respective E(max) values of 82.9±2.2% and 34.8±3.6%. The removal of endothelium almost abolished the relaxant effect of the extract. In addition, pre-treatment with N(w)-nitro-L-arginine-methyl ester (L-NAME, 100 µM), atropine (1 µM) or charybdotoxin (30 nM) plus apamin (30 nM), respective blockers of nitric oxide (NO) synthase, muscarinic receptors and endothelium-derived hyperpolarizing factor (EDHF), significantly reduced the observed effect of NSHE. By contrast, the cyclooxygenase (COX) inhibitor indomethacin (10 µM) or the K(+) channels blockers glibenclamide (10 µM), iberiotoxin (30 nM) and 4-amino-pyridine (4-AP, 1 mM) failed to modify the vasodilation. Finally, the acute intravenous injection of NSHE (1, 5, 10, 20 mg/kg) induced an immediate and transient hypotensive effect in anesthetized SHR and in WKY rats. CONCLUSIONS: This experimental animal study suggests that hydroalcoholic extract from the fruits of Nitraria sibirica Pall. induces vasorelaxation through an endothelium-dependent pathway involving NO synthase (NOS) activation, EDHF production and muscarinic receptor stimulation. Additionally, our results determine that this vasorelaxant effect is translated by a significant hypotensive effect.

Bioassay-guided isolation of vasorelaxant compounds from Ziziphora clinopodioides Lam. (Lamiaceae).

Ziziphora clinopodioides Lam. (Lamiaceae) is traditionally used in Uighur's medicine for the treatment of hypertension. Our study determined and evaluated the bioactive compounds by performing an activity-guided fractionation of a hydroalcoholic extract of the whole plant, using an in vitro model of rat isolated thoracic aortic rings. Seven compounds were identified as active principles: acacetin, apigenin, chrysin, thymonin, acetovanillone, 4-hydroxyacetophenone and ethyl 4-coumarate. Apigenin, chrysin and ethyl 4-coumarate were found to be the most effective. Our results provide the first evidence that the vasodilation induced by Z. clinopodioides Lam. is mediated, at least in part, by phenolic components.

Mechanisms of vasorelaxation induced by Ziziphora clinopodioides Lam. (Lamiaceae) extract in rat thoracic aorta.

AIM OF THE STUDY: Ziziphora clinopodioides Lam. (ZC) is widely used in Uyghur folk medicine for the treatment of hypertension diseases in Xinjiang, an autonomous region of China. To provide pharmacological basis for this traditional use, we explored the vasodilating effects of ZC and investigated the underlying mechanisms. MATERIALS AND METHODS: Activity of hexane (ZCHE), dichloromethane (ZCDE) and aqueous (ZCAE) extracts of ZC were evaluated on isolated rat aortic rings pre-contracted with phenylephrine (PE) or high KCl. The mechanisms were evaluated on ZCDE, the most potent extract. RESULTS: ZCDE-induced relaxation in endothelium-intact aortic rings pre-contracted with phenylephrine (PE, 10(-6) M) or high KCl (6×10(-2) M), with respective EC(50) values of 0.27±0.03 and 0.34±0.04 g/l. Mechanic removal of the endothelium did not significantly modify ZCDE-induced relaxation. In endothelium-denuded aorta pre-contracted with PE (10(-6) M), the vasorelaxant effect of ZCDE was significantly decreased by 4-amino-pyridine (10(-3) M), but not by glibenclamide (10(-4) M), iberiotoxin (3×10(-8) M) and thapsigargin (10(-7) M). In Ca(2+) free solution, ZCDE significantly inhibited extracellular Ca(2+)-induced contraction in high KCl and PE pre-contracted rings. Additionally ZDCE inhibited the intracellular Ca(2+) release sensitive to PE (10(-6) M). CONCLUSIONS: The results demonstrate that ZDCE exhibits endothelium-independent vasodilating properties that are mediated by inhibition of extracellular Ca(2+) influx through voltage- and receptor-operated Ca(2+) channels (VDDCs and ROCCs), by inhibition of Ca(2+) release from intracellular stores, and also by the opening of voltage-dependent K(+) channels.